The present invention relates to data networking, telecommunication networking, and, in one embodiment, to systems and methods for efficiently aggregating multiple Fibre-Channel links.
The Fibre-Channel standard defines a bi-directional link protocol, used to connect computers to disk drives and other peripherals. A typical Fibre-Channel link may have a bandwidth of 1063 Mbps and a span of up to 10 kilometers.
One typical application of Fibre-Channel is interconnecting computer CPUs with arrays of disk drive in large scale computing centers, as would be used in, e.g., financial transaction processing. For reasons of fault tolerance, it is desirable to locate redundant storage resources at remote locations. The advent of high data rate metropolitan optical networks including such networks based on the use of dense wave division multiplexing (DWDM) and/or SONET/SDH transport systems makes it possible to extend so-called storage area networks (SANs) that carry multiple Fibre-Channel links over distances much longer than 10 kilometers.
It is useful to apply the widely prevalent Fibre-Channel standard to communicate across DWDM networks and therefore minimize the need to redesign computing center equipment. Such DWDM networks can themselves employ protocol such as Gigabit Ethernet, 10 Gigabit Ethernet, SONET, etc. A single wavelength may thus carry e.g., a 1 Gbps, 10 Gbps data stream, etc. Fibre-Channel frames may be encapsulated within Gigabit Ethernet frames and/or SONET frames.
However, severe data transport inefficiencies may arise if Fibre-Channel links are assigned to, e.g., Gigabit Ethernet links, 10 Gigabit Ethernet links, or STS-48 SONET envelopes based on maximum Fibre-Channel throughput. Typically, the momentary aggregate bandwidth of the Fibre-Channel links will fall far short of the total of the maximum bandwidths. Therefore, a straightforward mapping of transport network capacities to maximum Fibre-Channel demands will result in unused capacity. It would be desirable to use capacity more efficiently and therefore reduce costs.
One way of providing Fibre-Channel over-subscription of transport network capacity is to use Fibre-Channel switches on each end. This scheme is, however, much more expensive and adds complexity relating to management of the Fibre-Channel switch equipment. And furthermore this scheme represents only a partial solution since certain scenarios cannot be accommodated.